Mechanical stoker drive



F. A. GRUETJEN MECHANICAL STOKER DRIVE March 1, 1949.

2 Sheets-Sheet 1 Filed April 28, 1945 INVENTOR.

w & M A I m. e 1 F A lax-key 1949- F. A. GRUETJEN MECHANICAL STOKER DRIVE 2 Sheets-Sheet 2 Filed April 28, 1945 INVEN TOR. fiederzb? A Gruezy'cn Patented Mar. 1, 1949 UNITED STATES PATENT OFFICE MEGHANIGAL STOKER. DRIVE Frederick A. Gruetjen, Milwaukee, Wis.,, assignor to A. 0. Smith Corporation, Milwaukee, Wis, a corporation of' New York Application April2:8, 1945, SeriaLNo; 590,791.

4" Claims. 1' i This invention relates to a mechanical stoker drive and has particular reference to the drive andcontrol mechanism for driving the feed screw of. the. ordinary coal stoker for house furnaces.

One object of the invention is to provide a stoker drive in which the wear on. drive parts. is held at a minimumv by elimination of substantial frictional engagement between parts.

Another object is to providea stoker drive tha has a=novel means of adjusting the amount of rotationalv movement of the feed screw for each increment. of, intermittent movement.

A further object is.- to provide a stoker. drive in which noise of operation is substantially eliminated.

Another object. is toprovide a stoker drive with aminimum of .parts to lower the initial cost thereof and the. cost on the replacement of parts.

Another object is to provide a stoker drive that can be readily removedfrom the stoker assembly.

These and other objects and advantages of the invention appear hereinafter in connection with the description of an embodiment of the inventionillustrated in the accompanying drawing.

In the. drawing:

Figure 1 is a front. end view of the stoker drive embodying the. features of the invention and with the cover removed and showing the parts. in one extreme of feeding movement;

Fig; 2 is a similar. view showing. the parts in the opposite extreme of feeding. movement;

Fig. 3 isa top planview of the. drive; and

Fig. 4 isasection. taken on lined-40f FigureB.

Referring to the drawings there isv illustrated an embodimentv of the. invention. comprising a frame I having front andrear partssecuredat the lower end portion thereof to rectangular base 2 andjoined at the upper portions thereof by a rod, 3. An outer cover 4 is provided to'cover the front... of the frame.

At one side of frame I, thedrivingmotor 5, only a portion of which is shown, is supported by cradles and. secured in place by the restraining strap 6. Strap 6 extends around the end of motor from a pin I secured to: the rear of frame I in the upper middle portion thereof to pin. 8 secured to the-lower end portion of the. frame at. the. side thereof. A turnbuckle 9 is employed to tighten strap 6 around. motor 5.

The bearing housing I!) extends laterally within the other side of frame I. Afiange II is carried bythe rear portion of the housing and is bolted or otherwise secured to frame I to hold housing II] in place. A drive shaft I2 extends longitudinally of housing III and is journalled for rotation therein by drivemotor. 5 through the. drive mechanism of. the invention as described hereinafter. Shaft IE2 serves. to .drivethe. feed screw,. notshown, of the stoken A. crank I3 extends diagonally upwardly through reinforced opening M1 of. the end head of the driving motor5, and; is d'ri'venin-anoscillating manner by. an eccentric ontheshaft of motor 5. Opening I4 in the endhead of the drivingmotor housingreceivespthe extendedendnof crank I3 and is of sufficient. dimensions to. permit ,oscillating movement of. the crank.

A shear pin I5. joinsthe upper end. of crank I3 to the arms. of oneendLof'the operating. lever IS.

The. lever I.6..extend's..laterally withinnframe I from the upperendloforank. I3.to.a position. above drive shaft I2. The end-10f," arms I! ofglever I6 at the position above. shaft I2..are.. substantially enlarged. The pin I8 extends. longitudinally of frame I through the upper portion of the enlarged end. of .arms. III. The pin. I9. extendslongitudinall-y of; frame. I through. the lower. portion of the enlarged end. of arms. IAL.

A drum 20 is keyed-to drive. shaft I 27 within frame I. AdrivebandLZI. extends around thecircumference of. drum 2]] andone endofthe. band is pivotedto .arm l-I' of. operating lever I61 .by the upper pin l8 and the other end is similarly pivoted to arm Ilfby lower pin II9; Theb'andanddrum serve to convert. the reciprocatcrymotion of the crank I3andfllever ILG to. rotary motion, to drive shaft I2.

One end of aretaining link. 22 is also secured to operatinglever I6, by pin Idto-constitutethe latter a fulcrum about which lever I5 operates. The link 22 extendslaterally withinrframe I. at a horizontal position. belowoperating. lever I 6 and is adjustablelongitudinally toiprovidefor shifting of the fulcrum oflever I6;

.A rod23 passes through. a. horizontal. slot 24 in the .outer end. of link. 22. Rod 23 extends longitudinally of frame I and is supported bathe front and rear parts thereof. The outer end of .rod 23. is .welded to. the crank-.onlever. 25 which is employed to rotate the. rod to thepositiomdesiredltfor adjustment of the. position. oflink 22.

That portion of rod. 23 lying in andladjacent slot .24. is outwardly: curved. as. at 2 6..to. form. a crank and the rotation ofthe. rod bylever 25 locates. curved. crank. portion. 26. of rod. 23tat different horizontal. positions within. slot 2llp-to limit the horizontal movement of link 22.

Lever 25 is marked coal and is manually adjusted by handle 21 to the position desired as indicated by locating pointer 28 thereof at the degree setting desired, the degree settings being defined on the forward frame plate I by degree marks from zero to one hundred.

Lever 25 is provided in the body portion thereof with an'arcuate slot 29 concentric to the end of rod 23 which pivotally supports the lever. A pin 30 extends through slot 29 and is welded at one end to frame I. The slot 29 limits the radial movement of lever 25. A look nut 3| is disposed on the outer end of pin 30 and is tightened. against lever 25 to hold it in place after the pointer 28 has been located at the setting desired, in order to limit the horizontal movement of link 22 under the reciprocal influence of band 2l' and lever l6.

In the operation of the stoker drive, at each forward stroke of crank 13 operating lever 16 is raised and pushed forward to the right carrying upper pivot pin I8 and lower pivot pin IS with it. During the forward stroke lever I6 tilts in a manner to loosen drive band 2! and permit it to slip clockwise around drum 20. Upon the return stroke of crank l3 and lever l'6 the band is tightened around drum 26 resulting in counterclockwise rotation of the drum and the drive shaft l2 to which the drum is keyed.

The clockwise rotation of band 2| about the drum 20 is limited by retaining link 22 when the outer end of slot 24 reaches rod 23 in the forward movement of the link. This limitation determines the counterclockwise rotation of the drum ,20upon return of the band 2|.

When the coal adjustment lever 25 has pointer 28 located at zero, no motion clockwise of band 2! can take place and therefore zero amount of feed'o'f coal occurs since drum 20-is not rotated on the return stroke of operating lever 16. The stroke is consumed in merely tilting lever it around lower pivot pin 19 as its fulcrum.

When pointer 28 of coal adjustment lever 25 is located at one hundred, the greatest amount of the stroke of crank I3 is utilized since the setting of the pointer in this manner permits maximum movementof link 22 to the right before the end of the slot reaches rod 23. Upon the return stroke of crank I3 themaximum counterclockwise rotation of drum 2!] is obtained with the maximum feed of coal to the stoker.

v The drum drive portion of the mechanical stoker drive of the invention is readily separated from the motor unit by removing shear pin l5 joining the upperend of crank l3 to operating lever IE. Pin I5 is of a construction to shear 01f in the event of any operational difficulties arising in the mechanism.

-' The invention provides a compact stoker drive that substantially eliminates wear on parts and which provides a simple device for adjusting the amount of coal fed to the stoker.

Various embodiments of the invention may be employed within the scope of the accompanying claims.

I claim:

1. Armechanlcal stoker drive comprising a drive shaft to drive a coal feed screw, a cylindrical drum secured to said shaft and rotatable therewith, a drive band encircling said drum and pivoted at one end to an operating lever and at the other end to a retaining link also pivoted to said operating lever, and means to tilt said operating lever upon said retaining link to move the pivot line of the retaining link and band in one direction to loosen the band out of frictional engagement with the drum and thereafter to return the lever to normal position and move the pivot line of the retaining link and band in the opposite direction to tighten the band on said drum and thereby rotate the same in the latter direction.

2. A mechanical stokerdrivecomprising a drive shaft to drive a coal feed screw, a cylindrical drum secured to said shaft and rotatable therewith, adrive band encircling said drum and pivoted at one end to an operating lever and at the other end to a retaining link also pivoted to said operating lever, means to tilt said operating lever upon said retaining link to move the pivot line of'the retaining link and band in one direction to loosen the band out of frictional engagement with the drum and thereafter to return the lever to normal position and move the pivot line of the retaining link and band in the opposite direction to tighten the band on said drum and rotate the same in the latter direction, and means to adjust the position of the retaining link circumferentially of the drum to limit the rotation of the cylindrical drum when the drive band is disposed in frictional engagement therewith.

3. A mechanical stoker drive, comprising a drive shaft to drive a coal feed screw, a cylindrical drum secured to said shaft and rotatable therewith, a drive band encircling said drum and pivoted at one end to an operating lever and at the other end to a retaining link also pivoted to said operating lever, a drive motor, a crank member oscillated by the motor shaft and connected to said operating lever to tilt the same and move the pivot line of the retaining link and band clockwise of the drum to loosen the band out of frictional engagement therewith and thereafter to return the lever to normal position and move the pivot line of the retaining link and band in a counter-clockwise direction to tighten the band on said drum nad rotate the same in a counterclockwise direction, a slot in the end of the retaining link opposite said drive band, a rod extending through said slot, and a lever to move said rod to different horizontal positions to regulate the horizontal movement of the retaining link and limit the rotation of said drum by said drive band when the latter is disposed in frictional engagement therewith.

4. In a mechanical stoker drive having a drum rotated by a drive band to drive a coal feed screw, a retaining link pivoted at one end to one end of said drive band, a slot in the other end of said link having a rod extending therethrough, and a crank member to move said rod to dilferent horizontal positions to regulate the horizontal movement of the retaining link andlimit the rotation of said drum by said drive band when the latter is disposed in frictional engagement therewith.

FREDERICK A. GRUETJEN.

REFERENCES CITED UNITED STATES PATENTS Name Date Palmer Sept. 23, 1884 Number 

